1. Field
The present invention relates generally to computing equipment and, more specifically to out-of-band management networks for data centers.
2. Description of the Related Art
Data centers are often used to house and interconnect large collections of computing devices, like servers, databases, load balancers, and high-performance computing clusters. Often, the computing devices are interconnected with two different networks: an in-band network for conveying the data upon which the computing devices operate, for example content in webpages, queries and query responses, and data for high-performance computing; and an out-of-band management network for conveying commands to the individual computing devices to manage their operation and for conveying information like sensor data indicative of the operation of the computing devices.
Out-of-band management serves a number of purposes, depending on the use case. Examples of out-of-band activity include remote serial console sessions for server management. Often, out-of-band management networks are used to manage security risk, by limiting the attack surface of a network that could be used to control the computing devices and segregating the in-band network that often receives data from the outside world. In some cases, out-of-band management networks are operative to control the computing devices even when the computing devices are turned off, for example, by accessing memory on computing devices that is persistent (like flash memory) to perform things like BIOS (e.g., UEFI) updates, read values, and the like. Other examples of activities include booting a device that is been turned off, remote installation of operating systems, updates, setting hardware clock speeds, updating or querying firmware versions, and the like.
In many cases, the terminal portion of the out-of-band network is made via RS-232 buses. In many cases, this requires expensive serial concentrators in the rack to deal with many separate connections. Generally, the RS-232 specification is meant for a point-to-point connectivity between devices and, in many cases, does not provide for multiple concurrent transmitting devices on a single bus. This often limits the use of specification-compliant buses and increases wiring costs.